2 projects with 2 separate boards are somehow sharing the same sprint and affecting each other

[Steve Hooczko]

How can a determine why 2 separate projects with 2 separate boards are somehow sharing the same sprint and affecting each other when editing. For example, renaming the sprint on one project/board changes the sprint name on the other project's board.

[Mikael Sandberg · Accepted solution]

This is very common, and the reason is that sprints are not project specific. Usually this happens if someone adds an issue to a sprint from within the issue details instead of using the board to drag and drop the issue into the sprint. Your only way around this is to find the issue that has the sprint used by the other board and then remove it from that issue. 

My recommendation is to always add issues to a sprint from the backlog of a board, not from within the issue itself in order to avoid this to happen.

[Trudy Claspill]

In addition to what @Mikael Sandberg , be aware of the following:

A sprint will display within a board if any of these conditions are met:

1. The sprint was created in that board.

2. The sprint contains an issue that matches the filter criteria for the board.

As Mikael said, issues can be added to sprints by editing the Sprint field in the issue itself.

In addition to Mikael's tip to encourage users to add issues to sprints only from the Backlog, another tip is to make sure that sprints are uniquely named to include some identification of the board or team that "owns" the sprint. Jira also does not require sprint names to be unique across the instance so multiple boards/teams might use the simple naming convention of Sprint 1, Sprint 2, Sprint 3, etc. for their sprints. This can lead to confusion when a user edits an issue directly to add it to "Sprint 1" - they can't tell which board/team's sprint they have selected!